Ignition switch shield housing



Aug. 24, 1948. A, HALLETT 2,447,749y

IGNITION SWITCH SHIELD HOUSING Filed June 1.5, 1942 ALF/25D HAL/ 577; INVENTOR.

BY I

ATTORNEYS.

Patented Aug. 24, 1948 Y 2,447,749 IGNITION SWITCH SHIELD HOUSING Alfred Hallett, Los Angeles, Calif., assignor, by mesne assignments, to Hallett Manufacturing Company, Inglewood, Calif., a corporation of California Application June 15, 1942', Serial No. 447,079

l 4 Claims.

This invention relates to the shielding and protection of electrical systems for internal combustion engines.

In my copending application Serial No. 427,621, filed January 21, 1942, now abandoned, for Shielding for electrical systems, to which the present application is in general related, I have shown and described certain elements of electrical systems protected and electrically shielded.

Free electrical radiations from ignition systems of internal combustion engines used in proximity to radio receiving apparatus are picked up in such apparatus and interfere with reception. This is a serious factor in the operation of airplanes, motorboats, submarines, military land vehicles, and all other types of mobile transportation employing radio equipment as Well as in stationary installations in proximity to radio equipment.

Various forms of shielding have been employed for the purpose of grounding electrical radiations but so far as I am aware no one prior to my present invention has shielded an ignition switch.

Another problem arises in connection with the exposure of the elements of ignition or electrical systems to weather, oil and gas leakage and the like. Under heavy duty and adverse weather or operating conditions moisture, water, oil and gas may be deposited on the switch, terminals, etc., unless protected by moisture-proof and waterproof enclosures. Inasmuch as cables lead to various parts of the switch, such protective means should include the regions where the cables enter the protective housing of the switch.

It is therefore an object of my invention to provide an electrical shielding for an ignition switch which combines the function of physical protection to the elements of the switch against weather and other adverse operating conditions which contribute to failure of the switch, deterioration of insulation, connections, etc.

It is a further and more specific object of my invention to provide a metallic shielding for an ignition switch, connectors and associated elements which completely encloses and grounds the same, avoiding openings or cracks through,

(C1. ZOO-168) be enclosed within the shielding and mounted upon a panel or dashboard in the usual position, and which shielding incorporates means for convenient access to the switch connections.

These and other objects of my invention will be made more apparent from a consideration of the full description and drawing.

In the drawing:

Figure 1 is a vertical cross-sectional view of my shield assembled with a conventional ignition switch.

Figure 2 is a cross-sectional view of the same taken on the line 2-2 of Figure 1.

In the drawing, a conventional ignition switch I0 is shown enclosed within a metal shield housing Il and mounted upon a panel or dashboard I2. The internal details of the switch, not being a part of my invention are not illustrated. It is of any standard push and pull type operated by a plunger I3, which reciprocates through a hollow mounting sleeve or stem I4 and housed within a box or case I5. The mounting sleeve III is secured to the case I5 and is threaded to receive a nut I6.

The housing Il is preferably of rectangular conguration to accommodate the switch box I5 with the walls of the housing spaced therefrom except at the iront where the base II of the switch box I5 abuts against the forward wall I8 of the shield housing. The housing is provided with a hole I9 in the wall I8 to accommodate the mounting sleeve I4; and the assembly of switch and shielding is mounted upon the panel I2 by screwing down the nut I6.

The switch can be centered and its rear end further supported by set screws 20 threaded through the upper and Ilower walls 2I and 22 of the housing, which screws further function in supporting the switch firmly in position as for example against any pressure exerted by a screw driver in loosening or tightening the connections hereinafter described.

The shield housing II is preferably made in two parts, a relatively deep box-like member IIa, as illustrated, and a cover member or plate 23 which is held down by cap screws 24 threaded into bosses 25 formed in the sides 26 and 21 of the member IIa.. Optionally a gasket 28 may be used for sealing the cover 23 upon the box. The housing should be of metal having substantially high conductive properties.

The switch is normally provided with connection 30 at which terminate cables 3|.

The cables 3| are provided with insulation 32 and a metal shielding 33. The shielding illustrated here is in the form of a woven metal sheathing but a tubular enclosure or other equivalent shielding for the cable may be employed.

The cable 3| is brought through the cover plate 23 -by a moisture-proof and water-proof terminal 34, full details of which are illustrated and described in my aforesaid copending application Serial No. 421621 now abandoned. Thev low tension lterminals are both the same and only one will be described. y

Each comprises a metal collar 31 formed With an annular shoulder 38 and screwedr into a threaded opening 39 in the cover plate 23. This collar has an internal annular ledge 40. Snuglyiittingf within the collar is an insulator 4 I. seating on the ledge All and being formed also with .a beveled seat 42 at the upper end. Resting in thisy seat.

is a frusto conical insulating gland 43 preferably of soft rubber. A metal bushing 44' having. a cylindrical portion through which the cable extends and a flat disc at the lower end is seated on the upper face of the gland 43. It is-Vpreferable that the cylindrical portion of the bushing` be inserted betweenV the cable shielding- 33' and the insulation' 32 of thev cable. vThe lower end of the shielding 33 should beispread outover the disc portion of the bushing, and a ferrule 46 having a iiange at its lower end rests upon the out-turned shielding andA serves to center the cable. A threaded cap 41. screws vdown on the collar 3l to secure the various parts tightly in` place:

Access to the connections 3U may be. obtained by removal of threaded plugs 50- in the upper and lower walls .2|l and 212 respectively of the housing.

In assembling the device the switch and boxlike mem-ber of the housing mayv be mounted upon thev panel or dash, and the cap or cover 23 with the terminals 3A thereafter attached, and

the connections 3i! completed through the openings" provided by the removal of plugs 50.

The terminals are locked securely to the housing'insuring4 aznei'cient and satisfactory connection with the switch and providing a moisture proof entry* of the cables into thev housing as well; as a complete grounding of the metal cable shielding to the housing. Y

Thus I have achieved an ignition switch shield assembly in which the switchl unit isY completely enclosed in a structural senseV as a protection Iagainst Water, oil and dirt, andl completely shielded electrically by a housing which has'high conductive properties and which is positively connected with the cable'A shieldingv serving todissipa'tev intoV the ground all electrical radiations occurring in the switch unit, all being: accomplished in association with a standard switch and mountable on a dashl without additionalv attachments.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, itV isA recognized that departures may be made therefrom within the scope of. my invention, which is not to be limited to the details disclosed herein 4but is to be accorded the full scope of the claims so as to. embrace any` and all equivalent structures.

Having described my invention, what; I' claim as new-and desire to secure. byLetters Patent isi:

1. In combination with any ignition switch havingA its moving parts except an operating'plunger housed ina box, and amounting sleeve reciprocably housing said plunger projecting from a flatl end. of said box and. provided with a.: nut

'be'. passed through a panel and said shield housingV and switch mounted on said panel by tightening saidl nut against said panel on the side thereof opposite said housing.

2. Incombinatien.y with an ignition switch havits moving parts except an operating plunger house-d in a box,` and a mounting sleeve reciprovcably housing` said plunger projecting from an end of said box and provided with a nut threadedthereon, a shield of high conductive properties completely enclosing said box comprising a housing formed with an end wall and a hole in said wall to accommodate said mounting sleeve, said box being positioned in said shield housing with said mounting sleeve extending through said hole and said endof said box abutting against said end wallv of said shield housing whereby said mounting, sleeve may be passedv through a panel and said shield housing and switch mounted on saidl panel by tightening said nut against said panel on. the side thereof opposite said housing,

and securing set screws for said box threaded i rightangles to the axis of said sleeve.

3'. A shielded switch assembly comprising a housing. of. conducting material having a flat end wall adapted to about a panel, an encased switch member in said housing having a iiat end wall in contact with the end wall of the housing and having. all other sides of said member spaced from surrounding. walls of the housing, means for securing the switch member and the housing to the panel comprising a Sleeve on the switch member extending throughA the housing end wall and the panel anda lock nut-on said sleeve drawn against the panel,` and means for positioning the switch member within the housingspaced from the housingwalls comprising a pair of oppositely disposed set screws extending through opposite housing wallsinto. contact with said switch member.

4. A shielded switch assembly comprising a housing. of conductingl material having a iiat end wall adapt-edito abut a panel, an encased switch member inf said housing having a flat end wall in contact with the end wall of the housing and having all other sides` of said member spaced from surrounding walls of the housing, means for securing the switch member and the housing to the/panelcomprising. a sleeve on the switch member extending. through the housing end wall and the panel andv a lock nut on said sleeve drawn against the panel, means for positioning the switch member within. the housing spaced from the housing. wallsv comprisingv a pair of oppositely disposedk set screwsV extending through opposite housing, walls into. contact with said switch member, binding posts on the switch element at an end` remote from. said ila-t end, apertures in the housing providing lateral. and endwise access to binding pos-ts. on. the. switch member within the housingv and. moisture proof closures. for said apertures.

ALFRED HALLETT. (Referenceson following' page) REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Bumiller Aug. 9, 1910 Teich July 3, 1928 Number 

